This is what Gus had. His immune system turned on his own red blood cells. He needed four units of donated blood to survive the week it took for his medication to work. Read his story.
What it is
Red blood cells carry oxygen. In IMHA the dog's immune system mistakes its own red cells for something foreign and destroys them, sometimes faster than the bone marrow can replace them. The dog becomes anemic within days, and the breakdown products of all those destroyed cells turn the gums and skin yellow.
Most cases in dogs are "primary" or idiopathic, meaning no trigger is found. Some are "secondary" to something else: a tick-borne infection, cancer, certain drugs or a recent vaccine. Middle-aged females and breeds like cocker spaniels, springer spaniels, poodles, Old English sheepdogs and Irish setters are over-represented.1
Warning signs
These signs mean an emergency vet visit today, not a wait-and-see.
Why transfusions
Immunosuppressive drugs (steroids, often with a second drug such as mycophenolate, cyclosporine or azathioprine) are the actual treatment, but they take days to a week or more to slow the destruction.2 Transfused red cells buy that time. Because the immune system is still active, transfused cells are destroyed too, so a dog with severe IMHA may need several units over a few days. That is why one sick dog can use up a hospital's entire supply.
Dogs with IMHA are also prone to blood clots, which is a leading cause of death, so most are put on an anticoagulant such as clopidogrel or heparin.2
What the research says
- The American College of Veterinary Internal Medicine published consensus statements in 2019 on how to diagnose IMHA1 and how to treat it.2 These are what most specialists follow.
- Reported survival to discharge is roughly 50 to 80 percent depending on the study, with most deaths in the first two weeks. A large study of 149 dogs found a high bilirubin, low platelets and needing many transfusions were linked to worse outcomes.3,4
- Therapeutic plasma exchange, which filters the antibodies out of the blood, is an emerging add-on for severe cases. A 2021 study of 146 dogs found dogs treated with plasma exchange did about as well as medically treated dogs even though they were sicker to start with.5 More on plasma exchange.
- Relapse happens in a minority of dogs, sometimes years later, so most vets recommend lifelong bloodwork checks.
How you can help
Dogs with these conditions survive because another dog's owner signed up. Check in one minute if your dog can donate, find a blood bank near you, or join the pack and share this page.
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Research and references
Peer-reviewed sources for what's on this page. Each link runs a PubMed search for the paper so you land on the abstract, and often the full text.
- 1Garden OA, Kidd L, Mexas AM, et al. ACVIM consensus statement on the diagnosis of immune-mediated hemolytic anemia in dogs and cats J Vet Intern Med. 2019;33(2):313-334. PubMed
- 2Swann JW, Garden OA, Fellman CL, et al. ACVIM consensus statement on the treatment of immune-mediated hemolytic anemia in dogs J Vet Intern Med. 2019;33(3):1141-1172. PubMed
- 3Piek CJ, Junius G, Dekker A, et al. Idiopathic immune-mediated hemolytic anemia: treatment outcome and prognostic factors in 149 dogs J Vet Intern Med. 2008;22(2):366-373. PubMed
- 4Weinkle TK, Center SA, Randolph JF, et al. Evaluation of prognostic factors, survival rates, and treatment protocols for immune-mediated hemolytic anemia in dogs: 151 cases (1993-2002) J Am Vet Med Assoc. 2005;226(11):1869-1880. PubMed
- 5Francey T, Etter M, Schweighauser A. Evaluation of membrane-based therapeutic plasma exchange as adjunctive treatment for immune-mediated hematologic disorders in dogs J Vet Intern Med. 2021;35(2):925-935. PubMed